Nucleotide sequence of Klebsiella pneumoniae lac genes.

The nucleotide sequences of the Klebsiella pneumoniae lacI and lacZ genes and part of the lacY gene were determined, and these genes were located and oriented relative to one another. The K. pneumoniae lac operon is divergent in that the lacI and lacZ genes are oriented head to head, and complementary strands are transcribed. Besides base substitutions, the lacZ genes of K. pneumoniae and Escherichia coli have suffered short distance shifts of reading frame caused by additions or deletions or both during evolutionary divergence from a common ancestral gene. Relative to corresponding E. coli sequences, the nucleotide sequences of the lacZ and lacY genes are 61 and 67% conserved, and the lacI genes are 49% conserved. A comparison of both nucleotide and amino acid sequences revealed that the K. pneumoniae and E. coli lacI genes and lac repressor proteins each are related to the galR gene and gal repressor of E. coli to about the same extent. In terms of evolutionary relationships, the divergence of the forerunner of the galR gene from an ancestral lac repressor gene preceded separation and differentiation of the K. pneumoniae and E. coli lac repressor genes.     

Seroprevalence of Chlamydophila pneumoniae in ischaemic heart disease

We investigated the presence of Chlamydophila pneumoniae antibodies in 125 patients with cardiovascular disease and in 128 controls. C. pneumoniae antibodies were measured by microimmunofluorescence assay. A significantly high prevalence of IgG C. pneumoniae antibodies at titre > or = 8 was found in patients (84%) in comparison to controls (47.6%). Considering as cut-off the IgG titre > or = 32, 52% of patients with coronaropathies and 18.75% of controls resulted positive (p < 0.0001). IgA C. pneumoniae antibodies were found in patients and controls without statistically significant differences. High C. pneumoniae antibodies (titre > or = 256) were found in 11% of patients with acute myocardial infarction (AMI) and in none of the controls. In patients, the percentage of IgG and IgA seropositivity increased with age and decreased in patients aged > 70 years. Only patients with AMI are at risk of having antibodies against C. pneumoniae (OR = 6.69). None of the known risk factors for cardiovascular disease was significantly associated with C. pneumoniae seropositivity IgG. This is the first report in our area on the possible association of C. pneumoniae IgG seropositivity and acute ischemic events.     

Heat-inactivated C. pneumoniae organisms are not atherogenic

We have previously shown that infection with Chlamydia pneumoniae can significantly exacerbate atherosclerotic lesions in LDLR-/- mice concurrently fed a high cholesterol diet in 6 or 9 months. We now report that a period of 4 month was sufficient for demonstrating the C. pneumoniae atherogenicity. However, heat inactivation of C. pneumoniae organisms completely abolished the ability of C. pneumoniae to exacerbate the atherosclerotic lesions, suggesting that viable organism infection may be required for the C. pneumoniae atherogenicity.     

Single tube real time PCR for detection of Streptococcus pneumoniae, Mycoplasma pneumoniae, Chlamydophila pneumoniae and Legionella pneumophila from clinical samples of CAP

We designed a multiplex real time PCR for rapid, sensitive and specific detection of Streptococcus pneumoniae, Legionella pneumophila, Chlamydophila pneumoniae and Mycoplasma pneumoniae. The study cases consisted of 129 patients with community acquired pneumonia (CAP). Bacteriological techniques were implemented for detection of the cultivable organisms. DNA were extracted from sputa, throat swabs, bronchoalveolar lavages and tracheal aspirates and used as templates in real time PCR. The primers and probes were designed for cbpA (S. pneumoniae), p1adhesin (M. pneumoniae), mip (L. pneumophila) and ompA (C. pneumoniae). After optimization of real time PCR for every organism, the experiments were continued in multiplex in a single tube. Of 129 CAP specimens, the positive cultures included 14 (10.85%) for S. pneumoniae, 9 (6.98%) for L. pneumophila and 3 (2.33%) for M. pneumoniae. Four specimens (3.10%) were positive for C. pneumoniae by real time PCR. The sensitivity of our real time PCR was 100% for all selected bacteria. The specificity of the test was 98.26%, 98.34%, 100% and 100% for S. pneumoniae, L. pneumophila, M. pneumoniae and C. pneumoniae, respectively. This is the first report on the use of multiplex real time PCR for detection of CAP patients in the Middle East. The method covers more than 90% of the bacterial pathogens causing CAP.     

Chlamydia pneumoniae respiratory infections in Taiwan

To understand the epidemiology of Chlamydia pneumoniae acute infections in Taiwan, we collected 116 paired and 244 single sera from patients suspected of C. pneumoniae infection and conducted microimmunofluorescence test. Eighty-three patients (83/360, 23%) met the diagnostic criteria of current C. pneumoniae infection. The C. pneumoniae infections were significantly higher in men than in women (P< or =0.0001) and were most frequent in the group of 40-49 year-olds, and the people older than 70 years old. C. pneumoniae infection often occurred in the late autumn lasting to the cold winter and in the transition period between the spring and summer.     

Infection of Acanthamoeba castellanii by Chlamydia pneumoniae.

Chlamydia pneumoniae is an intracellular respiratory pathogen, which, similar to Legionella, might have developed mechanisms to escape the intracellular bactericidal activity of both human host cells and amoeba. We therefore investigated the intracellular growth and survival of C. pneumoniae in Acanthamoeba castellanii by using cell culture, immunofluorescence microscopy, and electron microscopy. A castellanii was incubated with purified elementary bodies of C. pneumoniae TW 183 at a concentration of 10(6) inclusion-forming units (IFU)/ml to give a ratio of approximately 1 IFU of C. pneumoniae per amoeba. Quantitative determination of chlamydial growth within A. castellanii revealed viable and infective C. pneumoniae in the range of 10(4) to 10(5) IFU/ml between days 7 and 14 postinfection. Immunofluorescence analysis and transmission electron microscopy with subsequent immunogold staining confirmed evidence of infection of the amoebae by C. Pneumoniae and additionally revealed that C. pneumoniae entered the typical growth cycle. Our results show that amoebae allow the survival of C. pneumoniae, suggesting that amoebae may serve as an additional reservoir for Chlamydia or Chlamydia-related organisms.     

Lobar pneumonia caused by Mycoplasma pneumoniae.

Seven patients with Mycoplasma pneumoniae pneumonia presented with moderate to dense consolidation in one (in five patients) or more lobes. The diagnosis was suspected in five patients after failure to respond to 1 to 6 (average 2.6) antibiotics administered for 2 to 12 (average 7) days, and in one patient upon the development of hemolytic anemia. Clues to the diagnosis of nonbacterial pneumonia included a nonrespiratory viral-like prodromal period (in five), a nonproductive cough (in five), lack of rigors (in seven), recent "pneumonia" in family members (in ;three), normal total leukocyte and neutrophil counts (in six) and the absence of bacterial pathogens in smears and cultures of sputum (in all seven). The diagnosis of M. pneumoniae infection was supported by the presence of cold agglutinins (in a titre of 1.64 or greater) in ;the serum of five or six patients and was confirmed by diagnostic levels or increases in the titre of M. pneumoniae complement fixing antibodies. Awareness of the fact that M. pneumoniae can present as lobar consolidation and close attention to the clinical and laboratory data can usually suggest a nonbacterial cause and thus prevent delay in appropriate antibiotic treatment.     

Specificity of the microimmunofluorescence assay for the serodiagnosis of Chlamydia pneumoniae infections.

Chlamydia pneumoniae infections are mostly confirmed using an indirect microimmunofluorescence test for which potential cross-reactions between antigens from different chlamydial species are not well documented. Using this assay, 928 sera (507 subjects) submitted for Chlamydia pneumoniae serology were tested for specific IgM and IgG to this bacteria using the TW-183 antigen. IgM and IgG reactivities to Chlamydia trachomatis serotypes C, D, E, and L2 and Chlamydia psittaci strain 6BC antigens were also tested. A sample was interpreted as positive only when evenly fluorescent elementary bodies were observed. Twenty-five subjects (4.9%) showed serological evidence of recent Chlamydia pneumoniae infection (IgM positive and (or) IgG seroconversion); 11 of them also showed serological evidence of recent infection with at least one other chlamydial species. Specificity was 50 and 63% for IgM and IgG detection, respectively. These results suggest that mixed or temporally related infections might occur, or, more likely, that some Chlamydia pneumoniae IgM or IgG reactivities might be due to heterotypic antibodies.     

Protective activity of secreted proteins of Streptococcus pneumoniae and Klebsiella pneumoniae

Protective efficacy of secreted proteins of Streptococcus pneumoniae and Klebsiella pneumoniae cultivated on cardiocerebral broth and semisynthetic growth medium respectively was studied in vivo. Fraction with molecular weight 30 - 50 kDa obtained by the method of membrane fractionation had high protective efficacy. Two-dose immunization of mice with this fraction provided 80 - 100% protection from infection by homologous strains of S. pneumoniae and K. pneumoniae. Cross-protective activity of the fraction was revealed when infecting immunized mice by different K-types of K. pneumoniae. Blood sera of mice immunized with 30 - 50 kDa fraction possessed preventive features protecting from infection 90% of animals while 100% of death in the control group. It was determined that protective efficacy of the mentioned fraction was determined by protein-containing antigens because proteolytic disruption of the protein component resulted in loss of protective properties of the preparation.     

The incidence of Chlamydia pneumoniae lower respiratory tract infections among university students in northern California.

Chlamydia pneumoniae has recently been identified as a cause of lower respiratory tract infections. From March 1987 to March 1988, 259 university students-151 students with lower respiratory tract infections and 108 controls-from the University of California, Berkeley, were studied to determine the incidence and pattern of C pneumoniae lower respiratory tract infections. Serologic evidence of a recent C pneumoniae infection was found in less than 2%, and the organism was not isolated from any of the subjects. Despite the paucity of evidence of a recent infection, 47.5% of this university population showed serologic evidence of a previous C pneumoniae infection. The lower incidence of C pneumoniae infection in our population, when compared with previous reports, suggests that there may be geographic and temporal differences or fluctuations among populations.     

Fulminant Mycoplasma pneumoniae pneumonia.

The frequency of fulminant pneumonia due to Mycoplasma pneumoniae is relatively rare despite the high prevalence of Mycoplasma species infection in the general population. We recently encountered such a case and have reviewed the English-language literature on cases of M pneumoniae pneumonia that have resulted in respiratory failure or death. Due to host factors or on epidemiologic grounds, fulminant cases seem to be more common in young healthy adults, in males, and possibly in smokers among the 46 patients we found. An enhanced host cellular immune response may be responsible for the development of severe cases. A spectrum of small airways disease is characteristic, including cellular bronchiolitis and bronchiolitis obliterans with and without organizing pneumonia. Based largely on anecdotal experience, corticosteroid use may be salutary in patients with respiratory failure. For reasons that are not well known, the incidence of pulmonary thromboembolism is increased in fatal cases.     

Physical mapping of the Mycoplasma pneumoniae genome.

In order to study the genome organization of Mycoplasma pneumoniae a cosmid library of M. pneumoniae DNA was established using a newly designed cosmid vector (pcosRW2). From this library 32 overlapping clones were isolated covering a contiguous 720 kbp DNA segment representing about 90% of the genome assuming a genome size of about 800 kbp.     

Motility of Mycoplasma pneumoniae.

Cell of Mycoplasma pneumoniae FH gliding on a glass surface in liquid medium were examined by microscopic observation and quantitatively by microcinematography (30 frames per min). Comparisons were made only within the individual experiments. The cells moved in an irregular pattern with numerous narrow bends and circles. They never changed their leading end. The average speed (without pauses) was relatively constant between o.2 and 0.5 mum/s. The maximum speed was about 1.5 to 2.0 mum/s. The movements were interrupted by resting periods of different lengths and frequency. Temperature, viscosity, pH, and the presence of yeast extract in the medium influenced the motility significantly; changes in glucose, calcium ions, and serum content were less effective. The movements were affected by iodoacetate, p-mercuribenzoate, and mitomycin C at inhibitory or subinhibitory concentrations. Sodium fluoride, sodium cyanide, dinitrophenol, chloramphenicol, puromycin, cholchicin, and cytochalasin B at minimal inhibitory concentrations did not affect motility. The movements were effectively inhibited by anti-M. pneumoniae antiserum. Studies with absorbed antiserum suggested that the surface components involved in motility are heat labile. The gliding of M. pneumoniae cells required an intact energy metabolism and the proteins involved seemed to have a low turnover.     

Cerebral blood flow autoregulation in early experimental S. pneumoniae meningitis.

We studied cerebral blood flow (CBF) autoregulation and intracranial pressure (ICP) during normo- and hyperventilation in a rat model of Streptococcus pneumoniae meningitis. Meningitis was induced by intracisternal injection of S. pneumoniae. Mean arterial blood pressure (MAP), ICP, cerebral perfusion pressure (CPP, defined as MAP - ICP), and laser-Doppler CBF were measured in anesthetized infected rats (n = 30) and saline-inoculated controls (n = 30). CPP was either incrementally reduced by controlled hemorrhage or increased by intravenous norepinephrine infusion. Twelve hours postinoculation, rats were studied solely during normocapnia, whereas rats studied after 24 h were exposed to either normocapnia or to acute hypocapnia. In infected rats compared with control rats, ICP was unchanged at 12 h but increased at 24 h postinoculation (not significant and P < 0.01, respectively); hypocapnia did not lower ICP compared with normocapnia. Twelve hours postinoculation, CBF autoregulation was lost in all infected rats but preserved in all control rats (P < 0.01). Twenty-four hours after inoculation, 10% of infected rats had preserved CBF autoregulation during normocapnia compared with 80% of control rats (P < 0.01). In contrast, 60% of the infected rats and 100% of the control rats showed an intact CBF autoregulation during hypocapnia (P < 0.05 for the comparison of infected rats at normocapnia vs. hypocapnia). In conclusion, CBF autoregulation is lost both at 12 and at 24 h after intracisternal inoculation of S. pneumoniae in rats. Impairment of CBF autoregulation precedes the increase in ICP, and acute hypocapnia may restore autoregulation without changing the ICP.     

产ESBLs肺炎克雷伯菌的基因型和耐药性研究

超广谱β-内酰胺酶(extended spectrumβ-lactamase,ESBLs)与细菌耐药性密切相关,为了揭示产ESBLs肺炎克雷伯菌的基因型和耐药性,本研究在2017年1月至2018年9月期间,共检测了466例肺炎克雷伯菌感染的患者标本,并分析了产ESBLs肺炎克雷伯菌的基因型和耐药性。研究结果显示,466例患者中共检出562个肺炎克雷伯菌菌株。其中,呼吸内科的检出数最多(212株,37.72%),其次为重症监护科(106株,18.86%)。对于不同标本来源,痰液中检出菌数最多(331株),占总数的58.90%。562株肺炎克雷伯菌中共检测出237株产ESBLs(42.17%)。产ESBLs肺炎克雷伯菌对阿莫西林(89.03%)、替卡西林(87.34%)、氨苄西林(81.43%)的耐药率最高;而对替加环素(9.28%)、阿米卡星(6.75%)、亚胺培南(1.27%)和美罗培南(0.84%)的耐药率最低。237株产ESBLs的肺炎克雷伯菌菌株中,53.59%扩增出CTX-M型,48.95%扩增出TEM型,40.93%增出SHV型。另外,237株产ESBLs的肺炎克雷伯菌菌株中,产两个及以上的ESBLs的菌株共111株(46.84%)。     

Identification of a purC gene from Streptococcus pneumoniae.

A gene encoding 5'-phosphoribosyl-5-aminoimidazole-4-N-succinocarboxamide synthetase was identified in Streptococcus pneumoniae as a 708-bp segment of the genome encoding a 27,001-Da protein with strong similarity to known PurC proteins. The S. pneumoniae purC gene, found immediately adjacent to the competence induction genes, comAB, was cloned and sequenced. The predicted protein product of purC displayed substantial (> 40%) identity to the entire sequence of the PurC proteins of Bacillus subtilis and Escherichia coli. Function of the S. pneumoniae gene product was demonstrated by complementation of E. coli purC mutations.     

Detection of serum antibodies against Chlamydia pneumoniae by ELISA

Abstract Chlamydia pneumoniae causes pneumonia and other respiratory infections in children, adolescents and adults. We tried to evaluate the diagnostic value of detection of serum antibodies by ELISA for C. pneumoniae infections in Japanese children. Serum IgG, IgA and IgM antibodies to C. pneumoniae were determined by the microimmunofluorescence (MIF) test. Serum IgG and IgA antibodies were also determined by ELISA test kits. Results obtained by ELISA were compared with those obtained by MIF test. IgG antibody to C. pneumoniae was detected in 135 (39.5%) by ELISA and in 125 (36.5%) by MIF out of 342 sera from Japanese infants and children without respiratory infections (aged from 2 months old to 15 years old). IgA antibody to C. pneumoniae was detected in 129 (37.7%) by ELISA and in 117 (34.2%) by MIF out of 342 sera tested. Of 342 specimens 113 were IgG-positive by ELISA and MIF (sensitivity: 90.4%, specificity: 89.9%, r = 0.853). Of 342 sera 28 had IgG antibody titers of 1:256 and none had titers 1:512 or higher by MIF. Of 28 infants and children a total of nine were less than 4 years of age. On the other hand, of 342 specimens 99 were IgA-positive by ELISA and MIF (sensitivity: 84.6%, specificity: 86.7%, r = 0.769). Of 342 sera 16 had IgA antibody titers of 1:256 or higher by MIF. Of 16 infants and children, ten were less than 4 years of age. ELISA had excellent sensitivity and specificity relative to MIF test for detection of IgC and IgA antibodies to C. pneumoniae . It was suggested that C. pneumoniae infection in Japanese infants and children under 4 years of age was not infrequent.     

Nitrogen fixation specific regulatory genes of Klebsiella pneumoniae and Rhizobium meliloti share homology with the general nitrogen regulatory gene ntrC of K. pneumoniae.

We have determined the complete nucleotide sequences of three functionally related nitrogen assimilation regulatory genes from Klebsiella pneumoniae and Rhizobium meliloti. These genes are: 1) The K. pneumoniae general nitrogen assimilation regulatory gene ntrC (formerly called glnG), 2) the K. pneumoniae nif-specific regulatory gene nifA, and 3) an R. meliloti nif-specific regulatory gene that appears to be functionally analogous to the K. pneumoniae nifA gene. In addition to the DNA sequence data, gel-purified K. pneumoniae nifA protein was used to determine the amino acid composition of the nifA protein. The K. pneumoniae ntrC and nifA genes code for proteins of 52,259 and 53,319 d respectively. The R. meliloti nifA gene codes for a 59,968 d protein. A central region within each polypeptide, consisting of approximately 200 amino acids, is between 52% and 58% conserved among the three proteins. Neither the amino termini nor the carboxy termini show any conserved sequences. Together with data that shows that the three regulatory proteins activate promoters that share a common consensus sequence in the -10 (5'-TTGCA-3') and -23 (5'-CTGG-3') regions, the sequence data presented here suggest a common evolutionary origin for the three regulatory genes.     

Prevalence of Mycoplasma pneumoniae and Chlamydia pneumoniae in pneumonia patients in four major hospitals in Trinidad

The prevalence of current Mycoplasma pneumoniae and Chlamydia pneumoniae infections in patients with pneumonia in Trinidad, and the relationship between pneumonia and risk factors were investigated. Blood samples were collected from 132 patients diagnosed by attending physicians, as suffering from pneumonia at four hospitals in Trinidad. Serum samples were tested for M. pneumoniae IgM and IgG and C. pneumoniae IgM by the enzyme immunoassay (EIA). In addition, C. pneumoniae IgM and IgG were detected using microimmunofluorescence (MIF). A comprehensive questionnaire which addressed demographic information as well as risk factors for pneumonia was administered to patients. All analyses were done using the Statistical Package for Social Sciences (SPSS), version 9. Seroprevalences of 46.0% (58 of 126) were found for C. pneumoniae Ig M/G, and 66.7% (88 of 132) for M. pneumoniae Ig M/G. The difference was statistically significant (p < 0.01; chi2). Thirty-four percent (43 of 125) for C. pneumoniae Ig M/acute Ig G and 28.8% (36 of 125) of M. pneumoniae IgM were not statistically significant (p > 0.05; chi2). Hospital, gender and ethnicity of patients did not significantly (p > 0.05; chi2) affect the seroprevalence of the bacteria assayed for. However, the prevalence of C. pneumoniae (23.3%) in patients under 21 years old compared to other age groups was statistically significant (p = 0.043; chi2). Overall, the seroprevalence to both pathogens was not significantly (p > 0.05; chi2) affected by comorbidities and signs/symptoms. It was concluded that new infections by C. pneumoniae in pneumonia patients may be an important aetiological agent for the condition in Trinidad.     

Cloning of the complete Mycoplasma pneumoniae genome.

The complete genome of Mycoplasma pneumoniae was cloned in an ordered library consisting of 34 overlapping or adjacent cosmids, one plasmid and two lambda phages. The genome size was determined by adding up the sizes of either the individual unique EcoRI restriction fragments of the gene bank or of the XhoI fragments of genomic M. pneumoniae DNA. The values from these calculations, 835 and 849 kbp, are in good agreement. An XhoI restriction map was constructed by identifying adjacent DNA fragments by probing with selected cosmid clones.